GUIDE 6G8580 - Caterpillar

Machine ECM
The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the operator control switch (switch to battery) circuits of the machine.
Table 1
Machine ECM (MID 39)
DTC Code Description System Response
1834-2 Ignition Key Switch: Data Erratic, Intermittent, or Incorrect A Level 2 warning will activate. Possible causes for an FMI 2 Diagnostic code are:
The wire is intermittently shorted to the ground circuit while the machine is in operation.
The wire is intermittently shorted to + battery.
An intermittent open circuit exists.
Incorrect software loaded.
The ECM has failed. ECM failure is unlikely.
Illustration 1 g06008570
Schematic of the Operator Control Switch (Switch to Battery) circuits
Note: The preceding diagram is a simplified schematic of the connections for the operator control switch (switch to battery) circuits. The schematic is electrically correct. However, not all the possible harness connectors are shown.For the full Electrical Schematic of your specific Asphalt Paver, refer to the appropriate media. Refer to the "Electrical Schematic Reference" table within the Troubleshooting, General Information story in this document.Diagnostic Trouble Code Procedure
Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure. For sensors powered via the fuse panel, check the condition of the appropriate fuse before beginning the troubleshooting procedure.
Table 2
FMI 2 Troubleshooting
1. Check The Switch
A. Ensure that the key start switch and disconnect switch are OFF.
B. Disconnect the key switch from the machine harness.
C. Measure the resistance between Pin "4" and Pin "1".
D. Move the switch through the range of selections. Verify that there is continuity with the switch in the START and RUN positions.
The resistance should be less than 5 Ω when switch operation indicates continuity, and greater than 5K Ω when switch operation indicates no continuity. OK - The resistance is as expected.
Proceed to Test Step 2.
NOT OK - The resistance is not as expected.
Repair: Replace the switch. Verify that the new switch resolves the diagnostic code.
Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded